Director-linked funds trim Werewolf (NASDAQ: HOWL) stake via 141K-share sale

Rhea-AI Filing Summary

Entities affiliated with Werewolf Therapeutics director Luke Evnin sold 141,106 shares of common stock in open-market transactions. The sales occurred over three days at weighted average prices of about $0.48, $0.46 and $0.45 per share, with individual trades ranging between $0.44 and $0.49705.

The trades were executed under a pre-established Rule 10b5‑1 trading plan dated March 26, 2026. After these transactions, entities associated with Evnin indirectly hold 622,579 shares of Werewolf Therapeutics common stock, spread across several MPM investment vehicles.

Insider Trade Summary 10b5-1

Net Seller: 141,106 shares ($66,200)

Net Sell 3 txns

Insider EVNIN LUKE

Role null

Sold 141,106 shs ($66K)

Type	Security	Shares	Price	Value
Sale	Common Stock	32,556	$0.45	$15K
Sale	Common Stock	27,698	$0.46	$13K
Sale	Common Stock	80,852	$0.48	$39K

Holdings After Transaction: Common Stock — 622,579 shares (Indirect, See Footnotes)

Footnotes (1)

1. Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated March 26, 2026. The shares were sold as follows: 8,663 by MPM Asset Management LLC ("AM LLC"), 54,692 by MPM BioVentures 2014, L.P. ("BV 2014"), 3,648 by MPM BIoVentures 2014(B), L.P. ("BV 2014(B)"), 1,883 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 11,966 by MPM Oncology Innovations Fund, L.P. ("MPM OIF"). The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.46 to $0.49705 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. MPM BioVentures 2014 GP LLC and MPM BioVentures 2014 LLC ("BV LLC") are the direct and indirect general partners of BV 2014 and BV 2014(B). BV LLC is the manager of AM BV2014. MPM Oncology Innovations Fund GP LLC ("MPM OIF GP") is the general partner of MPM OIF. Luke Evnin is a member of AM LLC, a Managing Director of BV LLC and a manager of MPM OIF GP. The Reporting Person disclaims beneficial ownership of the securities except to the extent of his pecuniary interest therein. The shares are held as follows: 73,157 by AM LLC, 461,914 by BV 2014, 30,807 by BV 2014(B), 15,896 by AM BV2014 and 101,059 by MPM OIF. The shares were sold as follows: 2,968 by AM LLC, 18,736 by BV 2014, 1,250 by BV 2014(B), 645 by AM BV2014 and 4,099 by MPM OIF. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.455 to $0.4858 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The shares are held as follows: 70,189 by AM LLC, 443,178 by BV 2014, 29,557 by BV 2014(B), 15,251 by AM BV2014 and 96,960 by MPM OIF. The shares were sold as follows: 3,488 by AM LLC, 22,023 by BV 2014, 1,469 by BV 2014(B), 758 by AM BV2014 and 4,818 by MPM OIF. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.44 to $0.4557 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. The shares are held as follows: 66,701 by AM LLC, 421,155 by BV 2014, 28,088 by BV 2014(B), 14,493 by AM BV2014 and 92,142 by MPM OIF.

Key Figures

Total shares sold: 141,106 shares May 27 average price: $0.48 per share May 28 average price: $0.46 per share +4 more

7 metrics

Total shares sold 141,106 shares Aggregate shares sold across three open-market transactions

May 27 average price $0.48 per share Weighted average sale price for 80,852 shares on May 27, 2026

May 28 average price $0.46 per share Weighted average sale price for 27,698 shares on May 28, 2026

May 29 average price $0.45 per share Weighted average sale price for 32,556 shares on May 29, 2026

Post-transaction holdings 622,579 shares Indirect holdings by MPM-related entities after May 29, 2026 trades

Price range (highest series) $0.46–$0.49705 Range of individual sale prices referenced for one transaction series

Price range (lowest series) $0.44–$0.4557 Range of individual sale prices referenced for another series

Key Terms

Rule 10b5-1, weighted average price, pecuniary interest, beneficial ownership, +1 more

5 terms

Rule 10b5-1 regulatory

"Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated March 26, 2026."

Rule 10b5-1 is a regulation that allows company insiders to buy or sell their shares at predetermined times, even if they have access to non-public information. It acts like setting a schedule in advance for transactions, helping prevent accusations of unfair trading. This rule provides a way for insiders to plan trades transparently, giving investors confidence that these transactions are not based on hidden information.

weighted average price financial

"The price reported in Column 4 is a weighted average price."

Weighted average price is the average price of a security where each trade or component is counted according to its size, so bigger trades pull the average more than smaller ones. Think of it like calculating the average cost of a grocery haul where items you bought more of have greater influence on the final per-item cost. Investors use it to understand the true average price paid or received, judge execution quality, and compare trading performance against market movement.

pecuniary interest financial

"The Reporting Person disclaims beneficial ownership of the securities except to the extent of his pecuniary interest therein."

beneficial ownership financial

"The Reporting Person disclaims beneficial ownership of the securities except to the extent of his pecuniary interest therein."

Beneficial ownership means the person or entity that actually enjoys the benefits of owning shares or other assets — such as receiving dividends, voting rights, or price gains — even if the legal title is held in another name. For investors it matters because knowing who truly controls and profits from a company reveals who can influence decisions, exposes potential conflicts of interest or hidden concentration of power, and affects transparency and risk in the stock.

open-market sale financial

"transaction_action": "open-market sale""

An open-market sale is when a shareholder sells existing shares directly on a public exchange to any willing buyer, rather than through a private deal. Think of it like putting goods on a busy market stall where price is set by supply and demand; for investors it matters because such sales increase available supply, can put short-term downward pressure on the stock price, and signal changes in liquidity or investor confidence.

Form 4 Insider Transactions: What Each Field Means →

SEC Form 4

FORM 4

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

OMB Number:			3235-0287
Estimated average burden
hours per response:			0.5

Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

X

Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

1. Name and Address of Reporting Person^*

EVNIN LUKE

(Last) (First) (Middle)

C/O MPM BIOIMPACT LLC

399 BOYLSTON STREET, SUITE 1100

(Street)

BOSTON MASSACHUSETTS 02116

(City) (State) (Zip)

UNITED STATES

(Country)

2. Issuer Name and Ticker or Trading Symbol
Werewolf Therapeutics, Inc. [ HOWL ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director		10% Owner
	Officer (give title below)		Other (specify below)

2a. Foreign Trading Symbol

3. Date of Earliest Transaction (Month/Day/Year)
05/27/2026

6. Individual or Joint/Group Filing (Check Applicable Line)

X	Form filed by One Reporting Person
	Form filed by More than One Reporting Person

4. If Amendment, Date of Original Filed (Month/Day/Year)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	05/27/2026		S(1)		80,852(2)	D	$0.48(3)	682,833	I	See Footnotes(4)(5)
Common Stock	05/28/2026		S(1)		27,698(6)	D	$0.46(7)	655,135	I	See Footnotes(4)(8)
Common Stock	05/29/2026		S(1)		32,556(9)	D	$0.45(10)	622,579	I	See Footnotes(4)(11)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares

Explanation of Responses:

1. Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated March 26, 2026.

2. The shares were sold as follows: 8,663 by MPM Asset Management LLC ("AM LLC"), 54,692 by MPM BioVentures 2014, L.P. ("BV 2014"), 3,648 by MPM BIoVentures 2014(B), L.P. ("BV 2014(B)"), 1,883 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 11,966 by MPM Oncology Innovations Fund, L.P. ("MPM OIF").

3. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.46 to $0.49705 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

4. MPM BioVentures 2014 GP LLC and MPM BioVentures 2014 LLC ("BV LLC") are the direct and indirect general partners of BV 2014 and BV 2014(B). BV LLC is the manager of AM BV2014. MPM Oncology Innovations Fund GP LLC ("MPM OIF GP") is the general partner of MPM OIF. Luke Evnin is a member of AM LLC, a Managing Director of BV LLC and a manager of MPM OIF GP. The Reporting Person disclaims beneficial ownership of the securities except to the extent of his pecuniary interest therein.

5. The shares are held as follows: 73,157 by AM LLC, 461,914 by BV 2014, 30,807 by BV 2014(B), 15,896 by AM BV2014 and 101,059 by MPM OIF.

6. The shares were sold as follows: 2,968 by AM LLC, 18,736 by BV 2014, 1,250 by BV 2014(B), 645 by AM BV2014 and 4,099 by MPM OIF.

7. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.455 to $0.4858 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

8. The shares are held as follows: 70,189 by AM LLC, 443,178 by BV 2014, 29,557 by BV 2014(B), 15,251 by AM BV2014 and 96,960 by MPM OIF.

9. The shares were sold as follows: 3,488 by AM LLC, 22,023 by BV 2014, 1,469 by BV 2014(B), 758 by AM BV2014 and 4,818 by MPM OIF.

10. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.44 to $0.4557 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote.

11. The shares are held as follows: 66,701 by AM LLC, 421,155 by BV 2014, 28,088 by BV 2014(B), 14,493 by AM BV2014 and 92,142 by MPM OIF.

	/s/ Luke Evnin	05/29/2026
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.
* Form 4: SEC 1474 (03-26)

FAQ

What did the latest HOWL Form 4 filing report for Luke Evnin–linked entities?

The filing shows entities associated with director Luke Evnin sold 141,106 Werewolf Therapeutics shares in open-market trades. These transactions occurred over three days and reflect activity in investment vehicles managed by MPM affiliates, not direct personal holdings.

At what prices did HOWL shares sell in the recent insider transactions?

The reported weighted average prices were $0.48, $0.46 and $0.45 per share. Footnotes state the individual trades occurred in ranges between $0.44 and $0.49705, with detailed price breakdowns available upon request from the company or regulators.

How many Werewolf Therapeutics (HOWL) shares remain held by the Evnin‑related entities?

After the reported sales, entities associated with Luke Evnin indirectly hold 622,579 shares of Werewolf Therapeutics common stock. These are spread across several MPM investment vehicles, including AM LLC, BV 2014, BV 2014(B), AM BV2014 and MPM OIF.

Were the HOWL insider sales made under a Rule 10b5-1 trading plan?

Yes. A footnote states the transactions were effected under a Rule 10b5‑1 plan dated March 26, 2026. Such plans are pre-arranged trading programs that schedule trades in advance, which can make the timing less indicative of short-term sentiment.

Who actually sold the HOWL shares in this Form 4, Luke Evnin or related funds?

The shares were sold by MPM-affiliated entities, including AM LLC, BV 2014, BV 2014(B), AM BV2014 and MPM OIF. A footnote explains Evnin is associated with these entities and disclaims beneficial ownership beyond his pecuniary interest.

How many HOWL shares did each MPM entity sell in the reported transactions?

Footnotes show the 141,106 shares were divided among AM LLC, BV 2014, BV 2014(B), AM BV2014 and MPM OIF. Each footnote details specific share counts per entity for each trading day, reflecting how the overall sale was allocated across the funds.